/Engine/Source/Runtime/SignalProcessing/Public/DSP/SpectrumAnalyzer.h
Thread safe call to perform actual FFT. Returns true if it performed the FFT, false otherwise. If bUseLatestAudio is set to true, this function will flush the entire input buffer, potentially losing data. Otherwise it will only consume enough samples necessary to perform a single FFT.
bool PerformAsyncAnalysisIfPossible ( bool bUseLatestAudio )